Lamp housing for film projectors



Nov. 52, 1948.

' Filed ma 29. 1944 L. FRANKEL.

LAMP HOUSING FOR FILM PROJECTORS 2 Sheets-Sheet 1 Nov. 2, 1948. i 1... FRANKEL LAMP nousme FOR FILM PROJEGTORS 2 Sheets-Sheet 2 Filed May 29, 1944 IN V EN TOR. ra/z /e&

Patented Nov. 2. 1.943

P ENr OFFICE nousmo ton FILM l nomo'rons Leo Frankel, Chicago, ll]? t Application May 29, 1944, Serial Nels 3 11:32

' 5 Claims.

My invention relates jectors and more in particular to a method of and means for dissipating the heat developed by V the usual projection lamp.

' The present invention. is a continuation-in "p8.1li'0f my prior application Serial No. 343,487, filed July 1, 1940, and which has become Patent No. 2,354,6'79, datedAug'ust 1, 1944. 'Such' copending application discloses amultiple projector for projecting films of different sizes such as 8 tofmotion picture profThe portion of the apparatus shown in the drawings comprises a amp housing 10 in which aiamp II is supported on a base l2, the base l2 being rotated by suitable means such as a downwardly projecting handle 13. r A reflector. I4 is ,Jadaptedto reflect light from the lamp ii to condenser lenses l6 for delivery through a film and mm.v films and 16 mm. films, and, whilethe f present invention is particularly adapted-for use with projectors of the type disclosed in my co-.

pending application, .the invention nevertheless may have utility generally in any type of projector in which there is a problem of properly controllin and d ssipating the heat generated by a projection lamp. 7 a

My invention will be explained by reference to the accompanying drawings wherein- Fig. 1 is an elevational view partly in section showing'a lamp housing portion of a projector with the lamp and other apparatus associated therewith, the portion of the view shown in section being substantially along the section line l-l of Fig. 3;

Fig. 2 is a fragmentary vertical sectional view partly in elevation substantially at right angles to the section" of Fig. 1, the section being taken 3-3 of Fig. 1, looking in the direction of the.

to Fig. 1 but showing a I Fig. 6 is a vertical sectional view taken along the line 6-6 of Fig. 7, looking in the direction of the arrows; and

Fig. 7 is a fragmentary plan view of the embodiment shown in Figs. 5 and 6. I,shall. first describe the embodiment shown in Figs. 1 to 4, inclusive, and in connection therewith I wish to point out'that only so 'much of a projector has been illustrated as appears to be essential to a full understanding of the invention herein disclosed and claimed. Those skilled in the art are referred to mycopending application, above identified, for a further discussion of details of a projector of the type herein shown, such as arrangement of projection lenses, film transporting mechanism and the like.

projection lenses (not shown). A second refiector I1 is adapted to assist in concentrating light from the lamp II to a condensing lens I8 from which such light is adapted to be delivered toa mirror l9 and thence to condenser lenses 2| for projecting film of a different size than the light system includingcondenser lenses l6.

\ The lamp housing Ill is provided with a housing cap 22 and both the housing In and cap 22 are provided with cooling fins of suitable type.

Depending from the cap 22 is a tubular casing 23 which forms abafiie between the lamp [I and the lamp housing It). A gasket 24 or low heat conductivityis disposed between the lower surface of a flange 23 and the upper surface of the housing cap 22 and screws.26 extend through extensions of the flange 23' and into the housing ,cap 22 to mount the casing 23 firmly in position. A heat resisting gasket 21 is p'rovidedbetween the housing cap 22 and the lamp'housing Ill. The housing cap 22 is. suitably fastened to the lamp housing ill by conventional means (not shown).

A fan 28 is adapted to draw exterior air into the fan housing and to deliver such air through air duct 29 into the lamp housing at a point beneath the lower edge of casing 23. The fan 28 is driven by shaft 3| connected to a motor (not shown) disposed in motor housing 32. Air

delivered to the lamp housing In escapes through the upper portion of such lamp housing. It will be noted thattlie entire upper. portion of the casing 23. is open to permit free escape of air therefrom and it will be noted, also, that passage! ways 33 in the upper portion of the housing cap 22 between the exterior thereof and a depending skirt 34 permit the escape of some air around the outside or the casing 23. The casing 23 is apertured in the manner indicated in the drawings to permit light from the lamp H to reach v the reflectorsand also to reach the condenser lens. The casing 23, however, extends substantially to the bottom of the lamp H.

The projection lamp 1 I is of a type furnishing illumination of high intensity and. therefore, generating a substantial amount of heat which must be d ssipated to avoid having the parts of thcprojection apparatusreach too high a temperature and/or possibly injuring the film, particularly if the latter should be stopped to show a single picture during a projection sequence. The fan provides means for passing a stream of air through the housing at a relatively high rate of speed. The casing 23, which is preferably formed of heat conducting material. causes a substantial amount of the air to pass upwardly between the casing 23 and the lamp II. {The casing becomes quite hot .beca'use itis interposed betweenthe lamp and lamp housing; while the lampf housing itself remains relatively cool because thereis not a direct flow of heat waves to the lamp housing such as would occur if the shell23 were not employed; and the passage of air along both sides'of the casing keeps the casing cool enough so that it does not become a secondary heat,g enerator' of sufiicient intensity-to appreciably raise the temperature of the lamp housing. The housing material between said housing'and cap. a lamp.

disposed vertically in the housing, a casing susapertured housing cap,

pended from the cap and surrounding the lamp, and means for forcing air through said housing and out through said cap, a portion of such air, v passing between the lamp and such casing. 2. In a projectona lamp housing including an low heat conductivity disposed vertically in the housing, a casing sus- 1 pended from the cap and surrounding the lamp,

- and means for forcing air through said housing and out through said cap, a portion of such air passing between the lamp and suchcasing, saiq cap 22 is relatively warmer than the lamp'housing in because it supports the casing 23, butit is not as hot as the casing- 23 because of the interposition of low heat conductivity gasket 24. The gasket 21 limits heat flow from th relatively warmer cap 22 to the relatively cooler lamp housing III.

The lamp II is also kept adequately cool by the constant-movement of air across. its exterior surface, but the cooling is accomplished in such a way as not to interfere with the lightefiiciency' of the projection lamp. Those skilled in the art will understand that the lamp I I may be of various casing extending down almost to the bottom of such lemmand being apertured to permit light .-"delivery from the lamp tea point outside said 3.1In a projector, a lamphousing including an apertured housing. cap, low heat conductivity material between said housing and cap, a lamp :disp'osed vertically-in the housing, a casing ens-- pended from the cap and surrounding the lamp,

5 housing cap, and means for forcing. air

said housing and out through said cap, a

types used in the motion picture industry, a comment but the a r controlling casing is more nearly structurally identical with the casing shown in 1 my copending application above identified, of which this is a continuation-in-part. For convenience, and to simplify the description, I have employed the same reference characters in Figs. 5 to 7, inclusive, as employed in Figs. 1 to 4, inclusive, with, however, the numeral I as'a prefix to indicate modification. It will be noted that the casing I 23 extends down only to a point imme diately above the condenser lenses and reflectors, This construction permits the use of either stationary reflectors or of a reflector associated with the lamp base and rotatable with the lamp and base in the general manner disclosed in my co-' pending application. In this form of the invention there is relatively slight metal to metal contact between the casing I23 and the housing can I22.

The housing cap. nevertheless, will get relatively warmer than when employing the construct on of the first described embodiment but thegasket I21 of low heat conductivity material prevents the how of heat back from the housing cap I22 to the lamp housing 0.

I have described my invention by reference to structural details of two specific embodiments. It is understood that the scope of the invention is defined in the claims...

What I claim as new and desire to protect by Letters Patent of the United States .is:

1. ma projector, a lamp housing including an apertiu'ed housing cap, low heat conductivity low conductivity'material betweenthe casing and through portion of such air passing between the lamp and such casing, said casing extending 'down almost to the' bottom of such lamp. and being apertured tofpermit light delivery from the lamp toa point outside said casing.

4. In a projector; a lamp housing including a cap having a large center aperture, a lamp disposed vertically in the housing, a generally tubular casing surrounding the lamp and supported in said center cap aperture, said casing having an outfiarlng flange disposed above said cap, a gasket having low heat. conductivity disposed between said'fiange and cap, and means. ior forcing alrthrough said housing and-between said casing and lamp.

5. In a projector, a lamp housing including an apertured housing cap, a lamp disposed vertically in the housing, a casing disposed in the housing and surrounding the lamp, support means on said housing cap for said casing thermally insulating said casing from said housing, and means for forcing air through said housing and out through said cap, aportion of such air passing between the lamp and such-casing, said casing extending down from said housing cap almost to the bottom of such lamp, and being'apertured to permit light delivery from the lamp to a point outside 7 LEO narannlgons CITED The followingreierences are of record the file of this patent:

- UNI'I'ED STATES PA'IENTS f said casing.

Number Name Date 1,656.389 Nothstine Jan. 17;1928 1,919,595 Owens July 25, 1933 1,921,214 Carpenter Aug. 8, 1933 1,937,585 Luxmore Dec. 5, 1933 1,966,531 Tint July 17, 1934 2,033,038 Lee Mar. 3, 1936 2,165,681 Stechbart July 11, 1939 2,269,794 Stechbart Jan. 13, 1942 2,279,930 Howell Apr. 14, 1942 2,294,219 Woermann Aug. 25, 1942 Leonard Mar. 2, 1943 

